Method and system for sterilizing food packaging container or food filling system

ABSTRACT

The present invention provides a method of sterilizing a food packaging container or a food charging system, which comprises a chemical sterilizing treatment which involves contacting an aqueous sterilizing solution containing a hypochlorous acid-containing, chlorine-based sterilizing agent and a pH adjusting agent with the surface of a food packaging container or the surface of a line pipe, an instrument and a chamber in a food packaging system and a heat sterilizing treatment which involves increasing the temperature of the surface to be sterilized, the two sterilizing treatments being carried out simultaneously or in separate steps. The invention also provides a sterilizing device which has a predetermined sterilizing effect on a wide variety of microbial species, can be easily handled, does not corrode a treated surface over a prolonged period of time, is free of a pungent smell and does not require any special treatment for disposal of waste liquor.

TECHNICAL FIELD

[0001] The present invention relates to a method of sterilizing thesurfaces of food packaging containers such as PET bottles and plasticcups charged with various foods and drinks such as drinking water,juice, oolong tea and milk coffee and the surface of a line pipe, aninstrument or a chamber in a food charging system and to a devicetherefor, and in particular to a method which has a predeterminedsterilizing effect on a wide variety of microbial species, can be easilyhandled and does not corrode the surface of a line pipe, an instrumentor a chamber in a food charging system over a prolonged period and to adevice therefor. Further, the present invention relates to a sterilizingmethod which does not generate a pungent smell and does not require anyspecial treatment for disposal of waste liquor.

BACKGROUND ART

[0002] Conventionally, when PET bottles are to be sterilized with aperacetic acid-based sterilizing agent compounded with hydrogenperoxide, the PET bottles are sterilized by charging the bottles withthe sterilizing agent. After this sterilization, the charged sterilizingagent is discharged from the PET bottles, and the PET bottles are washedwith aseptic water to remove the sterilizing agent from the PET bottles(washing step).

[0003] To prevent hydrogen peroxide or peracetic acid from remainingafter the washing step, there is demand for reducing the concentrationof hydrogen peroxide and peracetic acid used to lower levels. However,when the concentration of the hydrogen peroxide and peracetic acid usedare reduced to lower levels, the sterilizing agent cannot demonstrate apotent sterilizing effect, and for sufficient sterilization, thereinevitably arises the economical problem of a longer sterilization time.

[0004] As the method of sterilizing PET bottles to solve the problem inthe prior art, there is an invention described in Japanese Patent No.3080347. The sterilization method of this prior art invention comprisesheating, at 60° C. or more, a peracetic acid-based sterilizing agentcontaining peracetic acid at a concentration of 1000 to 1500 ppm andfurther containing hydrogen peroxide and then jetting the sterilizingagent via a nozzle onto at least the internal surface of a PET bottle.

[0005] By heating the sterilizing agent at 60° C. or more, the inventiondescribed in Japanese Patent No. 3080347 supra could succeed insterilizing PET bottles in a shorter time without increasing theconcentration of the sterilizing agent. The sterilizing agent used inthis invention, however, is a highly acidic, peracetic acid-basedsterilizing agent compounded with hydrogen peroxide, so that aftersterilization of a food charging system, the resulting waste liquorshould be treated for disposal by reducing treatment, pH treatment orthe like, resulting in the problem of higher costs. Further, thesterilizing agent is based on peracetic acid and thus has a pungentsmell to make its storage and handling difficult, and it cannot beeasily handled.

[0006] As a conventional method of cleansing and sterilizing a foodpackaging container such as PET bottle, there is known a method ofcontacting hot water with the surface of a food packaging container or amethod of contacting a sterilizing agent such as hydrogen peroxidetherewith. Further, JP-A 7-291236 discloses that a hot-water sterilizingstep with hot water at 63° C. or more is combined with a chemicalsterilizing step with a sterilizing agent selected from the groupconsisting of hydrogen peroxide, peracetic acid, a mixture of hydrogenperoxide and peracetic acid, and sodium hypochlorite, and also that thissterilizing method is effective in sterilizing food containers.

[0007] The invention in JP-A 7-291236 supra can kill microorganismswithout using a large amount of the sterilizing chemical. Thesterilizing agent used in this invention, however, is a peraceticacid-based sterilizing agent which is so acidic that after sterilizationof a food charging system, the resulting waste liquor should be treatedfor disposal by reducing treatment, pH treatment or the like, resultingin the problem of higher costs. Further, the sterilizing agent has apungent smell to make its storage and handling difficult, and cannot beeasily handled.

[0008] In recent studies, it has been revealed that this sterilizingagent, when used in a conventional method, is not so effective againstsome microbial species. Accordingly, when there is demand for aneffective sterilizing effect on such microbial species, the chemicalshould be used in a larger amount, and therefore there arises problemssuch as very difficult treatment of the resulting waste liquor, etc.

[0009] The present invention is made to solve the above-describedproblems in the prior art, and the object of the present invention is toprovide a method capable of sterilizing the surface of a food packagingcontainer or a line pipe, an instrument and a chamber in a foodpackaging system in a shorter time without increasing the concentrationof a sterilizing agent and without causing a pungent smell and problemssuch as an adverse effect on a line pipe, an instrument and a chamberwall in a food packaging system, as well as a device therefor. Anotherobject of the present invention is to provide a novel sterilizing methodwhich does not require any special treatment for disposal of wasteliquor, and can limit successive introduction of a sterilizing agentunder heating to the minimum level.

DISCLOSURE OF INVENTION

[0010] The present invention relates to a method of sterilizing a foodpackaging container or a food charging system, which comprises achemical sterilizing treatment which involves contacting an aqueoussterilizing solution containing a hypochlorous acid-containing,chlorine-based sterilizing agent and a pH adjusting agent with thesurface of a food packaging container or the surface of a line pipe, aninstrument and a chamber in a food packaging system and a heatsterilizing treatment which involves increasing the temperature of thesurface to be sterilized, the two sterilizing treatments being carriedout simultaneously or in separate steps.

[0011] The present invention comprises a chemical sterilizing treatmentelement and a heat sterilizing treatment element which can be carriedout in separate steps or in the same step.

[0012] Preferably, the aqueous sterilizing solution has a pH value of 4to 8, and is contacted in a heated state at 40° C. to 80° C.

[0013] Particularly preferably, the chemical sterilizing treatment andthe heat sterilizing treatment are carried out simultaneously.

[0014] According to another aspect of the invention, the chemicalsterilizing treatment which involves contacting an aqueous sterilizingsolution containing a hypochlorous acid-containing, chlorine-basedsterilizing agent and a pH adjusting agent may be combined with the heatsterilizing treatment which involves increasing the temperature of thesurface to be sterilized.

[0015] Preferably, the pH of the aqueous sterilizing solution is 4 to 8,and the heat sterilizing treatment is carried out at a temperature of63° C. or more.

[0016] The method of the present invention may further comprisecontacting a surfactant.

[0017] The hypochlorous acid-containing, chlorine-based sterilizingagent is preferably at least one selected from hypochlorous acid andhypochlorite. The effective chlorine concentration of the hypochlorousacid-containing, chlorine-based sterilizing agent is preferably 200 to2000 ppm.

[0018] The pH adjusting agent is preferably at least one member selectedfrom the group consisting of alkali metal hydroxides, alkaline earthmetal hydroxides, inorganic acids or salts thereof and organic acids orsalts thereof.

[0019] The surfactant is preferably a surfactant derived from apolyvalent alcohol. The surfactant is preferably at least one memberselected from the group consisting of polyglycerol fatty ester, glycerinfatty ester, sucrose fatty ester, sorbitan fatty ester, calciumstearoyllactate, propylene glycol fatty ester, lecithin such as soybeanlecithin, yolk lecithin and plant lecithin, soybean saponin and beetsaponin.

[0020] The heat sterilizing step can be carried out by using at leastone of hot water, steam, hot air and a hot pack.

[0021] The heat sterilizing step can be carried out as a pre-step of thechemical sterilizing step, and the heat sterilizing step can be carriedout by using at least one of hot water, steam and hot air. Further, theheat sterilizing step can be carried out as a post-step of the chemicalsterilizing step, and the heat sterilizing step can be carried out byusing a hot pack.

[0022] Further, the present invention provides a device for sterilizinga food packaging container or a food charging system, comprisingsterilizing agent-contacting means in which an aqueous sterilizingsolution containing a hypochlorous acid-containing, chlorine-basedsterilizing agent and a pH adjusting agent is contacted in a heatedstate with the surface of a food packaging container or the surface of aline pipe, an instrument or a chamber in a food charging system byjetting, dipping or spraying. In the device of the present invention,the hypochlorous acid-containing, chlorine-based sterilizing agent andthe pH adjusting agent can be contacted in a state heated at 40° C. to80° C. with the surface by jetting, dipping or spraying. Further, afterthe surface is contacted with the hypochlorous acid-containing,chlorine-based sterilizing agent, the surface contacted with thesterilizing agent can be washed with aseptic water by jetting, dippingor spraying. Further, a surfactant can also be contacted.

[0023] According to the present invention, the sterilizing agent used asan aqueous solution containing at least one selected from hypochlorousacid and hypochlorite, a surfactant and a pH adjusting agent can becontacted with the surface to be sterilized to sterilize the surface ina very short time without increasing the concentration of thesterilizing agent. Further, the pH of the chlorine-based sterilizingagent such as hypochlorous acid is regulated near neutrality, whereby asafe and excellent sterilizing effect can be achieved with suppressedgeneration of a chlorine gas, and further the pH of the sterilizingagent comprising a mixture of the chlorine-based sterilizing agent and asurfactant is near neutrality, and thus the sterilizing agent does notrequire any special treatment for disposal of waste liquor, and can beused in a food charging system with no or less generation of a pungentsmell. In addition, the present invention can be applied not only to thesurface of a food packaging container but also to the surface of a linepipe, an instrument and a chamber in a food charging system as theobject of sterilization.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] According to the present invention, a wide variety of microbialspecies can be killed without increasing the concentration of thesterilizing agent and without causing a pungent smell and problems suchas an adverse effect on a line pipe, an instrument and a chamber in afood packaging system.

[0025] In particular, the maximum sterilizing effect can be achieved byregulating the pH value of the sterilizing agent near neutrality, andfurther the pH value of the sterilizing agent is near neutrality, andtherefore the sterilizing agent does not require any particular devicefor disposal of waste liquor, and can be easily handled with lessgeneration of a pungent smell. Further, the sterilizing agent can beapplied not only to the surface of a food packaging container but alsoto the surface of a line pipe, an instrument and a chamber in a foodcharging system as the object of sterilization.

[0026] The heated chlorine-based sterilizing agent containinghypochlorous acid is preferably the one with less pungent smell and notrequiring any special treatment for disposal of waste liquor. Thissterilizing agent can be obtained from sodium hypochlorite, a chlorinegas, chloride of lime, and sodium dichloroisocyanurate and the like.

[0027] To regulate the pH value of the sterilizing agent near neutralityfrom the viewpoint of preventing generation of a chlorine gas andachieving a safe and excellent sterilizing effect, the pH value of thehypochlorous acid-containing, chlorine-based sterilizing agent of thepresent invention is regulated preferably in the range of pH 4 to 8 witha pH regulating agent. The pH value is preferably pH 5 to 8, morepreferably pH 5 to 7, still more preferably pH 6 to 7. In particular,the pH value is regulated preferably just before the sterilizing agentis contacted with an object of sterilization. The pH regulating agentused for this purpose ispreferablya food additive such as succinic acid,citric acid, gluconic acid or L-tartaric acid.

[0028] When the chemical sterilizing treatment and the heat sterilizingtreatment are simultaneously carried out, the hypochlorousacid-containing, chlorine-based sterilizing agent of the presentinvention is heated preferably 40° C. or more, more preferably over 50°C., most preferably in the range of 65° C. to 80° C.

[0029] The effective chlorine concentration in the hypochlorousacid-containing, chlorine-based sterilizing agent of the presentinvention is preferably 200 to 2000 ppm, still more preferably 200 to600 ppm.

[0030] The hypochlorous acid-containing, chlorine-based sterilizingagent of the present invention is contacted with the surface to besterilized successively preferably for 10 seconds or more, morepreferably for 60 to 120 seconds. The hypochlorous acid-containing,chlorine-based sterilizing agent of the present invention is madeeffective against a wide variety of microbial species by pH adjustmentand heating, and it was revealed that for example, when Bacilluscirculans is to be killed as an objective microorganism, themicroorganism cannot be killed at ordinary temperatures even upon beingcontacted with the sterilizing agent for 120 seconds, but can be killedin a short time of about 60 seconds by previously heating thesterilizing agent at 65° C. or more. To demonstrate a higher sterilizingeffect, therefore, not only the pH adjustment and heating of thesterilizing agent but also the contact time should be sufficientlyexamined.

[0031] The object of sterilization in the present invention is theinternal and external surfaces of food packaging containers such as PETbottles and plastic cups.

[0032] The object of sterilization in a PET bottle aseptic chargingsystem is the surface of each of an aseptic water line in a bottlerinser, a cap in a cap sterilizing machine, an aseptic water line in acap rinse shoot, an instrument arranged in a charging chamber and thechamber. Further, the present invention can also be applied not only toa PET bottle aseptic charging system, but also to an aseptic chargingsystem such as a plastic-cup aseptic charging system and to a hot-packcharging system.

[0033] The sterilizing agent of the present invention is a hypochlorousacid-containing, chlorine-based sterilizing agent whose pH is regulatednear neutrality, so that even if a small amount of the sterilizing agentremains on the internal surface of a food packaging container aftersterilization, the sterilizing agent is not particularly harmful to thehuman body, and therefore the step of washing the food packagingcontainer with aseptic water after the sterilizing step can beeliminated depending on the type of charged food, thus bringing about asignificant effect on reduction in the production process and inproduction costs.

[0034] The sterilizing agent can be added with a small amount of asurfactant and used as a mixed sterilizing agent to further improve thesterilizing effect.

[0035] In another aspect of the sterilizing method of the invention, thesterilizing agent used as an aqueous solution comprising the sterilizingagent, the surfactant and the pH adjusting agent can be heated.

[0036] In another aspect of the invention, the pH adjusting agent ischaracterized by being at least one member selected from the groupconsisting of alkali metal hydroxides, alkaline earth metal hydroxides,inorganic acids or salts thereof and organic acids or salts thereof, andthe pH value of the aqueous solution is characterized by being 4 to 8.

[0037] In another aspect of the invention, the surfactant ischaracterized by being a surfactant derived from a polyvalent alcohol.

[0038] In a still another aspect of the invention, the surfactant ischaracterized by being a surfactant which can be added to foods, and ischaracterized by being at least one member selected from the groupconsisting of polyglycerol fatty ester, glycerin fatty ester, sucrosefatty ester, sorbitan fatty ester, calcium stearoyllactate, propyleneglycol fatty ester, lecithin such as soybean lecithin, yolk lecithin andplant lecithin, soybean saponin and beet saponin.

[0039] The sterilizing agent used in another aspect of the inventioncomprises a sterilizing agent used as an aqueous solution containing atleast one selected from hypochlorous acid and hypochlorite, a surfactantand a pH adjusting agent. In the present invention, the “surfactant”means a polyvalent alcohol-derived surfactant for improving wettingproperties of the surface of a microorganism, and is composed ofglycerin fatty acid ester, polyglycerol fatty ester, propylene glycolfatty ester, polypropylene glycol fatty ester, sucrose fatty ester,sorbitan fatty ester, alkyl polyglycoside, etc. The “surfactant whichcan be added to foods” means a surfactant allowable as a food additiveby law. The surfactant which can be added to foods is divided roughlyinto a chemically synthesized surfactant and a naturally occurringsurfactant, and the chemically synthesized surfactant which can be usedincludes polyglycerol fatty ester, glycerin fatty ester, sucrose fattyester, sorbitan fatty ester, calcium stearoyllactate, propylene glycolfatty ester, etc., and the naturally occurring surfactant which can beused includes lecithin such as soybean lecithin, yolk lecithin and plantlecithin and soybean saponin, beet saponin, etc.

[0040] As the finally used aqueous solution containing at least oneselected from hypochlorous acid and hypochlorite, use can be made of achlorine-based sterilizing agent such as alkali metal hypochlorite,chloride of lime, or sodium dichloroisocyanurate, among which sodiumhypochlorite is preferable.

[0041] The compounding ratio of the surfactant which can be added tofoods to the chlorine-based sterilizing agent is determined suitably inconsideration of the microbial species to be sterilized, the type offood to be charged, the type of packaging container, etc. For example,when the internal and external surfaces of a PET bottle for drinkingwater and the internal and external surfaces of a cap are sterilized ina PET bottle aseptic charging system, the ratio of the concentration ofthe surfactant:the effective chlorine concentration of the chorine-basedsterilizing agent in the mixed sterilizing agent can be in the range of1:20 to 1:1 to achieve an excellent sterilizing effect in a short time.

[0042] In another aspect of the invention, the mixed sterilizing agentis produced desirably by adding a pH adjusting agent to hypochlorousacid or a salt thereof to regulate the pH value of the chlorine-basedsterilizing agent near neutrality and then mixing it with a surfactantif necessary. From the viewpoint of preventing generation of a chlorinegas and achieving a safe and excellent sterilizing effect, the pH valueis preferably pH 4 to 8, more preferably pH 5 to 8, still morepreferably pH 5 to 7, further more preferably pH 6 to 7. The pHadjusting agent used for this purpose is at least one member selectedfrom the group consisting of alkali metal hydroxides, alkaline earthmetal hydroxides, inorganic acids or salts thereof, and organic acids orsalts thereof. The alkali metal includes alkali metal hydroxides,alkaline earth metal hydroxides, inorganic acids or salts thereof, andorganic acids or salts thereof. Among these, organic acids or saltsthereof are preferable from the viewpoint of improvement of thesterilizing effect. The alkali metal hydroxides and alkaline earth metalhydroxide include sodium hydroxide, potassium hydroxide, calciumhydroxide, etc. The inorganic acids or salts thereof includeshydrochloric acid, sodium sulfate, sodium nitrate, sodium chloride,sodium carbonate, potassium hydrogen carbonate, sodium hydrogencarbonate, potassium hydrogen carbonate, magnesium sulfate, magnesiumnitrate, magnesium chloride, trisodium phosphate, tripotassiumphosphate, disodium hydrogen phosphate, dipotassium hydrogen phosphate,sodium dihydrogen phosphate, potassium dihydrogen phosphate, sodiumpolyphosphate, etc. The organic acids or salts thereof includessaturated dibasic acids such as malonic acid, succinic acid, glutaricacid, adipic acid and sebacic acid or salts thereof, unsaturated dibasicacids such as fumaric acid and maleic acid or salts thereof, and citricacid, acetic acid, lactic acid, malic acid, tartaric acid and gluconicacid, etc. The pH adjusting agent is preferably a saturated dibasic acidor a salt thereof, more preferably a saturated dibasic acid containing 3to 10 carbon atoms or a salt thereof, still more preferably succinicacid or a salt thereof from the viewpoint of the safety of thepharmaceutical preparation. From the viewpoint of improvement of thesterilizing effect, the pH adjusting agent is preferably an organic acidor a salt thereof, particularly preferably succinic acid, citric acid,gluconic acid or L-tartaric acid as a food additive.

[0043] The mixed sterilizing agent of the present invention is usedpreferably at an effective chlorine concentration of 1 to 5000 ppm, morepreferably 5 to 2000 ppm, still more preferably to 1000 ppm.

[0044] When the microbial species to be killed is for example Bacilluscereus, the sterilizing agent of the present invention can be used atordinary temperatures to achieve a sufficient sterilizing effect bycontacting it in a short time of about seconds, but it was found thatwhen the microbial species to be killed is for example Bacilluscirculans or Chaetomium sp., the microorganism can be sterilized in ashort time of about 10 seconds by previously heating the sterilizingagent at 65° C. or more. Accordingly, the sterilizing agent ispreviously heated preferably at65° C. or more, more preferably at 65 to100° C. in order to exhibit a sufficient sterilizing effect on a widevariety of microbial species.

[0045] When the sterilizing agent of the present invention is used as anaqueous solution containing a combination of at least one selected fromhypochlorous acid and hypochlorite, a surfactant which can be added tofoods, and a pH adjusting agent, there is no particular harm to thehuman body even if a very small amount of the sterilizing agent remainson the internal surface of a food packaging container aftersterilization, and therefore the step of washing the food packagingcontainer with aseptic water after the sterilizing step can beeliminated depending on the type of charged food, thus bringing about asignificant effect on reduction in the production process and inproduction costs.

[0046] In another aspect of the invention, the heat sterilizingtreatment and the chemical sterilizing treatment are each carried out inseparate steps. In the heat sterilizing step, the temperature of thesurface to be sterilized is increased with a combination of one or twoor more of hot water, steam, hot air and/or a hot pack.

[0047] For sterilizing every kind of microbial species sufficiently,heat sterilization is carried out desirably at a temperature of 63° C.or more. That is, the surface to be sterilized is desirably heated to63° C. by contacting the surface to be sterilized with hot water, steam,hot air, a heated drink etc. A sufficient sterilizing effect on Bacilluscirculans, Chaetomium sp. etc. cannot be achieved without heating thesterilizing agent in the chemical sterilizing step, but thesemicroorganisms can be sufficiently killed by heating the surface to besterilized at 63° C. or more with hot water etc. in the heat sterilizingstep. Accordingly, when Bacillus circulans or Chaetomium sp. is to bekilled, the sterilizing agent may be used at ordinary temperatures (20to 50° C.) in the chemical sterilizing step insofar as the heatsterilization is carried out at a temperature of 63° C. or more.

[0048] The heat sterilizing step using a combination of one or two ormore of hot water, steam and hot air may be carried out as a pre- orpost-step of the chemical sterilizing step. The heat sterilizing stepmay be carried out as a post-step by using a hot pack (hot charge). Thehot pack is convenient because it is not necessary to arrange a specialheating unit except for a previously arranged hot pack unit.

[0049] The mixed sterilizing agent for sterilization in a separate stepin the present invention is used preferably at an effective chlorineconcentration of 1 to 5000 ppm, more preferably 5 to 2000 ppm, stillmore preferably 5 to 1000 ppm.

[0050] As described above, microbial species such as Chaetomium sp. arekilled by heat sterilization at 63° C. or more in the heat sterilizingstep, and thus the sterilizing agent of the present invention can beused at ordinary temperatures (20° C. to 50° C.)

TECHNICAL ADVANTAGES OF THE INVENTION

[0051] According to the present invention, the hypochlorousacid-containing chlorine-based sterilizing agent in a state regulated inthe range of pH 4 to 8 and heated at 40° C. or more is contacted withthe surface to be sterilized thereby effecting sterilization in a veryshort time without increasing the concentration of the sterilizingagent, as described above. By regulating the sterilizing agent in therange of pH 4 to 8, the sterilizing agent can achieve the maximumsterilizing effect, does not require any special device for treatment ofwaste liquor, and can be handled easily with less generation of apungent smell. The sterilizing agent can be applied not only to thesurface of a food packaging container, but also to the surface of a linepipe, an instrument or a chamber in a food charging system.

[0052] The sterilizing agent of the present invention is not harmful tothe human body, and therefore the step of washing a food packagingcontainer with aseptic water after the sterilizing step can beeliminated depending on the type of charged food, which can contributeto reduction in the production process and in production costs.

[0053] According to another aspect of the present invention, thesterilizing agent used as an aqueous solution containing at least oneselected from hypochlorous acid and hypochlorite, a surfactant and a pHadjusting agent is contacted with the surface to be sterilized therebyeffecting sterilization in a very short time without increasing theconcentration of the sterilizing agent. By regulating the sterilizingagent consisting of a mixture of a chlorine-based sterilizing agent anda surfactant near neutrality, the sterilizing agent does not require anyspecial treatment for disposal of waste liquor and can be used in a foodcharging system with no or less generation of a pungent smell. Thesterilizing agent can be applied not only to the surface of a foodpackaging container, but also to the surface of a line pipe, aninstrument or a chamber in a food charging system.

[0054] Further, the sterilizing agent of the present invention can,depending on the type of charged food, eliminate the step of washing afood packaging container with aseptic water after the sterilizing step,which can contribute to reduction in the production process and inproduction costs.

[0055] According to another aspect of the present invention, thesterilizing agent contains at least one selected from hypochlorous acidand hypochlorite, a surfactant and a pH adjusting agent, and thereforethe pH of the chlorine-based sterilizing agent such as hypochlorous acidis regulated near neutrality, and the sterilizing agent as a mixture ofthis sterilizing agent and a surfactant is near neutrality, is thus freeof a pungent smell and does not require any special treatment fordisposal of waste liquor. Further, the heat sterilizing step is carriedout as a pre- or post-step of the chemical sterilizing step so that evena microbial species which unless the sterilizing agent is heated, cannotbe killed with the sterilizing agent can be killed in the heatsterilizing step, and thus heating of the sterilizing agent is notnecessary. Accordingly, decomposition reaction due to heating of thesterilizing agent does not occur, and a wide variety of microbialspecies can be killed in a short time without requiring successiveintroduction of the sterilizing agent, and thus the amount of thechemical used can be limited to the minimum level.

BRIEF DESCRIPTION OF THE DRAWINGS

[0056]FIG. 1 is a diagram showing one embodiment of the device forcarrying out the method of the present invention;

[0057]FIG. 2 is a sectional view showing one example of the method ofsterilizing a plastic bottle in the present invention; and

[0058] Numerals in these drawings are as follows:

[0059]5: bottle sterilizing machine (unit for contacting a sterilizingagent)

[0060]6: bottle rinser

[0061]7: filler

[0062]8: temporarily capping machine

[0063]9: capper

[0064]FIG. 3 is a schematic diagram showing another example of thesterilization method of the present invention.

[0065] Numerals in the drawing are as follows:

[0066]101: bottle delivery unit

[0067]102: bottle hot water sterilization zone

[0068]103: bottle chemical sterilization zone

[0069]104: rinse zone

[0070]105: filling and sealing zone

DESCRIPTION OF EMBODIMENTS OF THE INVENTION AND EXAMPLES

[0071] Hereinafter, one embodiment of the unit for carrying out thepresent sterilization method applied to a PET bottle aseptic chargingsystem is described by referring to FIG. 1.

[0072] In FIG. 1, a PET bottle aseptic charging system 1 includes a PETbottle delivery unit 2 composed of a belt conveyer etc. and asterilizing chamber 3 and a charging chamber 4 from the upstream side tothe downstream side in the direction of bottle delivery. The sterilizingchamber 3 and the charging chamber 4 are each maintained at the germfreelevel of class 10000. The sterilizing chamber 3 is provided with abottle sterilizing machine 5 and a bottle rinser 6 from the upstreamside, and the charging chamber 4 is provided with a filler 7, atemporarily capping machine 8 and a capper 9 from the upstream side.Note that, reference numeral 20 is an operation room.

[0073] The bottle sterilizing machine 5 constituting means of contactinga sterilizing agent in the sterilizing device of the present inventionsterilizes the internal surface and both of the internal and theexternal surfaces of a PET bottle, and allows a hypochlorousacid-containing, chorine-based sterilizing agent to be brought intocontact with the surface of a PET bottle to be sterilized. Thesterilizing agent is supplied from a sterilizing agent-feeding tank 12via a pipe 11 to the bottle sterilizing machine 5, and in the bottlesterilizing machine 5 as shown in FIG. 2, surfaces such as a bottominternal surface 31, a bottom external surface 32 and a wall internalsurface 33 of a PET bottle 30 in an inverted state are sterilized byjetting the sterilizing agent via first and second nozzles 10 and 20attached to the pipe 11. Alternatively, the bottle sterilizing machine 5may be constituted such that the PET bottle is sterilized by dipping thebottle in a sterilizing agent bath charged with the sterilizing agent orby spraying the surface of the PET bottle to be sterilized with thesterilizing agent. The sterilization time is preferably 10 to 120seconds.

[0074] The bottle rinser 6 is supplied via a pipe 13 with aseptic waterfrom an aseptic water tank 14 arranged in a germfree atmosphere. Thebottle rinser 6 is provided with an aseptic water-jetting nozzle (notshown), and aseptic water is jetted to the PET bottle aftersterilization, to wash out the sterilizing agent remaining on thesurface of the PET bottle. Thereafter, the PET bottle in an invertedstate is turned upside down and simultaneously fed to a filler 7. Thebottle rinser 6, pipe 13, aseptic water tank 14 and asepticwater-jetting nozzle constitute means of contacting the PET bottle withaseptic water in the device of the present invention.

[0075] The filler 7 is a device for charging the PET bottle with a drinksuch as drinking water or juice, and is supplied with a drink via a pipe15 from a drink tank 16. PET bottle caps discharged from a cap-feedingdevice 17, sterilized with a mixed sterilizing agent in a capsterilizing machine 18 and washed with a cap rinse shoot 19 are suppliedto a temporarily capping machine 8. In the temporarily capping machine8, a supplied cap is mounted on the head of the drink-containing PETbottle just after being discharged from the filler, and the cap istemporarily attached thereto by light rotation and then sent to a capper9. In the capper 9, the cap is fixed to the PET bottle by tightlyturning the cap.

[0076] The PET bottle is supplied by the PET bottle delivery unit 2 froma PET bottle source (not shown) to the bottle sterilizing machine 5 inthe sterilizing chamber 3, and the surface of the PET bottle to besterilized is contacted for a predetermined time with the sterilizingagent by jetting, dipping or spraying. After sterilization, the PETbottle is sent to the downstream bottle rinser 6 where the sterilizingagent is washed out with aseptic water. Then, the PET bottle is sent tothe filler 7 in the charging chamber 4 and charged with a drink. The PETbottle charged with a drink is temporarily fit with a cap in thetemporarily capping machine 8, tightly fit with the cap finally in thecapper 9, and delivered to the outside of the system.

[0077] The foregoing is an embodiment of the present invention appliedto a PET bottle aseptic charging system, and when the present inventionis applied to a plastic cap charging system, the PET bottle may bechanged to a plastic cup, and the cap to a lid material, and the capperto a sealer (the temporarily capping machine is not necessary).

[0078] Hereinafter, one embodiment of the unit for carrying out thesterilizing method of the present invention applied to a PET bottleaseptic charging system is described by referring to FIG. 1.

[0079] In FIG. 1, a PET bottle aseptic charging system 1 includes a PETbottle delivery unit 2 composed of a belt conveyer etc. and asterilizing chamber 3 and a charging chamber 4 from the upstream side tothe downstream side in the direction of bottle delivery. The sterilizingchamber 3 and the charging chamber 4 are each maintained at the germfreelevel of class 10000. The sterilizing chamber 3 is provided with abottle sterilizing machine (sterilizing agent-circulating device) 5 anda bottle rinser 6 from the upstream side, and the charging chamber 4 isprovided with a filler 7, a temporarily capping machine 8 and a capper 9from the upstream side. Note that, reference numeral 20 is an operationroom.

[0080] The bottle sterilizing machine 5 constituting means of contactingthe sterilizing agent of the present invention sterilizes the internalsurface and both of the internal and the external surfaces of a PETbottle, and allows the mixed sterilizing agent of a surfactant which canbe added to foods and a chlorine-based sterilizing agent to be broughtinto contact with the surface of a PET bottle to be sterilized. Themixed sterilizing agent is supplied from a sterilizing agent-feedingtank 12 via a pipe 11 to the bottle sterilizing machine 5, and in thebottle sterilizing machine 5 as shown in FIG. 2, surfaces such as abottom internal surface 31, a bottom external surface 32 and a wallinternal surface 33 of a PET bottle 30 in an inverted state aresterilized by jetting the sterilizing agent via first and second nozzles10 and 20 attached to the pipe 11. Alternatively, the bottle sterilizingmachine 5 may be constituted such that the PET bottle is sterilized bydipping the bottle in a mixed sterilizing agent bath charged with themixed sterilizing agent or by spraying the surface of the PET bottle 30with the mixed sterilizing agent. The sterilization time is preferably10 to 80 seconds. The PET bottle may be contacted in a non-invertedstate with the mixed sterilizing agent.

[0081] The bottle rinser 6 is supplied via a pipe 13 with aseptic waterfrom an aseptic water tank 14 arranged in a germfree atmosphere. Thebottle rinser 6 is provided with an aseptic water-jetting nozzle (notshown), and aseptic water is jetted to the PET bottle aftersterilization, to wash out the mixed sterilizing agent remaining on thesurface of the PET bottle. Thereafter, the PET bottle in an invertedstate is turned upside down and simultaneously fed to a filler 7.

[0082] The filler 7 is a device for charging the PET bottle with a drinksuch as drinking water or juice, and is supplied with a drink via a pipe15 from a drink tank 16. PET bottle caps discharged from a cap-feedingdevice (sterilizing agent-circulating device) 17, sterilized with themixed sterilizing agent in a cap sterilizing machine 18 and washed witha cap rinse shoot 19 are supplied to a temporarily capping machine 8. Inthe temporarily capping machine 8, a supplied cap is mounted on the headof the drink-containing PET bottle just after being discharged from thefiller, and the cap is temporarily attached thereto by light rotationand then sent to a capper 9. In the capper 9, the cap is fixed to thePET bottle by tightly turning the cap.

[0083] The PET bottle is supplied by the PET bottle delivery unit 2 froma PET bottle source (not shown) to the bottle sterilizing machine 5 inthe sterilizing chamber 3, and the surface of the PET bottle to besterilized is contacted for a predetermined time with the mixedsterilizing agent by jetting, dipping or spraying. After sterilization,the PET bottle is sent to the downstream bottle rinser 6 where the mixedsterilizing agent is washed out with aseptic water. Then, the PET bottleis sent to the filler 7 in the charging chamber 4 and charged with adrink. The PET bottle charged with a drink is temporarily fit with a capin the temporarily capping machine 8, tightly fit with the cap finallyin the capper 9, and delivered to the outside of the system.

[0084] The foregoing is an embodiment of the present invention appliedto a PET bottle aseptic charging system, and when the present inventionis applied to a plastic cap charging system, the PET bottle may bechanged to a plastic cup, and the cap to a lid material, and the capperto a sealer (the temporarily capping machine is not necessary).

[0085] The sterilizing method of the present invention is described inmore detail by referring to FIG. 3. FIG. 3 is a conceptual diagramshowing one example of the method of sterilizing the internal surface ofa bottle to be sterilized, and the heat sterilizing step is carried outwith hot water. In FIG. 3, reference numeral 101 is a bottle deliverydevice composed of a belt conveyer etc., 102 is a bottle hot-watersterilizing zone, 103 is a bottle chemical sterilizing zone providedwith a sterilizing agent-feeding nozzle, 104 is a rinsing regionprovided with an aseptic water-jetting nozzle, and 105 is acharging/sealing zone.

[0086] The bottle hot-water sterilizing zone 102 is provided with anozzle capable of moving through the opening of a bottle, and from whichhot water is jetted. The whole external surface of the bottle beforesterilization is sterilized with hot water at 63° C. or more and thendelivered in an inverted state (with the opening facing downward) to thebottle hot-water sterilizing zone 102. In the bottle hot-watersterilizing zone 2, the nozzle is transferred into the opening of abottle, and hot water at 63° C. or more is jetted onto the internalsurface of the bottle. Therefore, microbial species on the internalsurface of the bottle are killed with hot water, and there remain onlymicrobial species not killed with hot water.

[0087] The bottle sterilized in the bottle hot-water sterilizing zone102 is delivered by the bottle delivery unit 101 to the bottle chemicalsterilizing zone 103. In the bottle chemical sterilizing zone 103, theaqueous sterilizing solution is sprayed via a sterilizing agent-feedingnozzle into the bottle (spray system), whereby the sterilizing agent iscontacted with the whole internal surface of the bottle. Themicroorganisms not killed by the hot water are thereby killed, and allthe microorganisms capable of growing in foods to be introduced into thebottle are killed. Because microorganisms to be hardly killed with thesterilizing agent are killed before sterilization with the sterilizingagent, the concentration of the sterilizing agent is reduced to a lowerlevel. In the foregoing, sterilization with the sterilizing agent iscarried out in a spray system, but the sterilizing agent may be storedin a tank to dip a bottle in the sterilizing agent or to fill it withthe sterilizing agent. In the method described above, only the internalsurface of the bottle is sterilized with the sterilizing agent, but as amatter of course, the external surface of the bottle may be sterilizedwith the sterilizing agent in order to achieve more reliablesterilization.

[0088] The bottle chemically sterilized with the sterilizing agent inthe bottle chemical sterilizing zone 103 is delivered by the deliveryunit 101 to a rinsing zone 104. In the rinsing zone 104, aseptic waterat ordinary temperatures or aseptic hot water is jetted onto at leastthe internal surface of the bottle, whereby the sterilizing agentadhering to the bottle is removed from the surface of the bottle. Theconcentration of the sterilizing agent used is at a lower level asdescribed above, and thus the concentration of the sterilizing agentadhering to the bottle sent to the rinsing zone 104 is low, and thesterilizing agent can be removed easily and certainly with a smallamount of aseptic water or aseptic hot water.

[0089] After rinsing, the bottle in an inverted state is turned upsidedown by bottle-inverting means (not shown), then sprayed with germfreeair and simultaneously sent by the bottle delivery device 101 to acharging chamber, that is, a charging/sealing zone 5. Thecharging/sealing zone 5 is maintained at a level of class 100 or lesswhere the bottle is charged with a food or drink such as milk coffee bya charging unit known per se. The charging/sealing zone 105 is providedwith a filer 106, a temporarily capping machine 7 and a capper 108 fromthe upstream side.

[0090] The filler 106 is a device for charging a bottle with a drinksuch as drinking water, juice etc., and is supplied with a drink via apipe 109 from a drink tank 110. Caps discharged from a cap-feedingdevice 111, sterilized with hot water in a cap hot-water sterilizingzone 112, chemically sterilized with the chemical in a cap chemicalsterilizing zone 13 and washed with a cap rinse shoot 114 are suppliedto a temporarily capping machine 107. In the temporarily capping machine107, a supplied cap is mounted on the head of the drink-containingbottle just after being discharged from the filler 106, and the cap istemporarily attached thereto by light rotation and then sent to a capper108. In the capper 108, the cap is fixed to the bottle by tightlyturning the cap. Thereafter, the bottle is inspected in a productexamination zone (not shown) to finish the whole process.

[0091] In the example in FIG. 3, the bottle hot-water sterilizing zone102 is arranged before the bottle chemical sterilizing zone 3, so thathot-water sterilization can be carried out before chemicalsterilization, but the bottle hot-water sterilizing zone 2 may bearranged after the bottle chemical sterilizing zone 103 so thathot-water sterilization can be carried out after chemical sterilization.In this case similar to the above case where chemical sterilization isfirst carried out, hot-water sterilization and chemical sterilizationcompensate for each other, and thus the concentration of the chemicalcan be reduced to a lower level. In addition, when hot-watersterilization is carried out after chemical sterilization, hot-watersterilization is carried out simultaneously with rinsing of the chemicalused in the chemical sterilizing step and remaining on a food container,and the bottle treatment time including the time of sterilization andsubsequent rinsing can be reduced.

[0092] The chemical can be used in a circulating system or spent up inone process.

[0093] In the above example, the heating step and sterilizing step arecarried out in separate zones, but in the same zone, sterilization maybe carried out after heating, or heating may be carried out aftersterilization, or heating and sterilization can be simultaneouslycarried out (two nozzles are used for simultaneously spraying hot waterand the chemical) In the last case, the system can be simplified.

EXAMPLES Example 1

[0094] To demonstrate the effectiveness of the sterilizing method of thepresent invention, the sterilizing effect of the method on the internalsurface of a PET bottle among the surfaces of food packaging materials,line pipes, instruments or chambers was examined as an example.

[0095] As a chlorine-based sterilizing agent, a pharmaceuticalpreparation (sterilizing agent) was prepared by diluting sodiumhypochlorite with water and then adding a sufficient acid to the finallyused solution to adjust its pH as described below.

[0096] A test microorganism was allowed to adhere to the internalsurface of a PET bottle in an amount of 104 cfu/bottle (intended level),and the internal surface of the PET bottle was sterilized under testconditions described later. After sterilization, the bottle was chargedwith a medium (microbial spores; standard liquid medium), capped with anaseptic cap and stored for 1 week (microbial spores; standard liquidmedium). After storage, the sterilizing effect on the adheringmicroorganism was determined by evaluating the medium with the nakedeye. In the table, “+” indicates the presence of the adheringmicroorganism, while “−” indicates the absence of the adheringmicroorganism. TABLE 1 Sterilizing effect on Bacillus circulansEffective chlorine concentration: 200 ppm Number of microorganisms Testadhering to the surface Temperature Sterilization time (second)microorganisms (cfu/cm2) (° C.) pH 10 60 120 300 Bacillus circulans 1.2× 10⁴ 80 10 + + + + circulans spores 8 − − − − 6 − − − − 4 − − − −2 + + + + 65 10 + + + + 8 + − − − 6 + − − − 4 + − − − 2 + + + + 5010 + + + + 8 + + − − 6 + + − − 4 + + − − 2 + + + + 40 10 + + + + 8 + + +− 6 + + + − 4 + + + − 2 + + + + 25 10 + + + + 8 + + + + 6 + + + +4 + + + + 2 + + + +

[0097] TABLE 2 Sterilizing effect on Bacillus circulans spores Effectivechlorine concentration: 400 ppm Number of microorganisms Test adheringto the surface Temperature Sterilization time (second) microorganisms(cfu/cm2) (° C.) pH 10 60 120 300 Bacillus circulans 1.2 × 10⁴ 6510 + + + + spores 8 − − − − 6 − − − − 4 − − − − 2 + + + + 50 10 + + + +8 + − − − 6 + − − − 4 + − − − 2 + + + + 40 10 + + + + 8 + + − − 6 + + −− 4 + + − − 2 + + + + 25 10 + + + + 8 + + + − 6 + + + − 4 + + + −2 + + + +

Example 2-1

[0098] To confirm the effectiveness of the sterilizing method of thepresent invention, the sterilizing effect of the method on the internalsurface of a PET bottle as an object of sterilization was examined.

[0099] As at least one selected from hypochlorous acid and hypochlorite,sodium hypochlorite was diluted with water and then adjusted to pH6.3±0.3 with succinic acid as the pH adjusting agent. Among surfactantswhich can be added to foods, polyglycerol fatty ester was used as thesurfactant and mixed therewith, and the mixed aqueous solution was usedat the concentrations shown in Tables 3 and 4. The effective chlorineconcentrations in Tables 3 and 4 were determined by the iodine methodJIS K-0101. In the comparative example, a sterilizing agent consistingof only an aqueous sodium hypochlorite solution (pH 10) whose pH was notregulated with a pH adjusting agent.

[0100] As the test microorganism, Bacillus cereus spores were allowed toadhere to the internal surface of a PET bottle in an amount of 106cfu/bottle (intended level), and the internal surface of the PET bottlewas sterilized under the test conditions shown in Table 3 below. Aftersterilization, the bottle was charged with a standard liquid medium,capped with an aseptic cap and stored for 1 week. After storage, thesterilizing effect on the adhering microorganism was determined byevaluating the medium with the naked eye. The results of determinationare shown in Table 3. In the table, “+” indicates the presence of theadhering microorganism, while “−” indicates the absence of the adheringmicroorganism. TABLE 3 Sterilizing effect on Bacillus cereus spores,Number of polyglycerin microorganisms aliphatic Effective Test adheringto the surface ester chlorine Temperature Sterilization time (second)microorganism (cfu/cm2) (ppm) (ppm) (° C.) 10 20 30 60 Bacillus cereus5.0 × 10⁶ 200 400 25 − − − − spores 35 − − − − 50 − − − − 65 − − − − 80− − − − 0 400 25 + + + + 35 + + + + 50 + + + + 65 + + + + 80 + + + +

Example 2-2

[0101] As test microorganisms, microbial spores i.e. Bacillus circulansspores and fungal spore i.e. Chaetomium sp. ascospores were selected,and the same mixed sterilizing agent as in Example 1 was used tosterilize PET bottles under the test conditions shown in Table 4 below.After sterilization, the bottle with the Bacillus circulans spores wascharged with a standard liquid medium, the bottle with Chaetomium sp.ascospores was charged with a potato dextrose standard liquid medium,and each bottle was capped with an aseptic cap and stored for 1 week,and then the medium was determined with the naked eye. The results ofdetermination are shown in Table 4. TABLE 4 Sterilizing effect onBacillus circulans spores, and sterilizing effect on Chaetomium sp.ascospores Number of polyglycerin microorganisms aliphatic EffectiveTest adhering to the surface ester chlorine Temperature Sterilizationtime (second) microorganism (cfu/cm2) (ppm) (ppm) (° C.) 10 20 30 60Bacillus circulans 7.0 × 10⁵ 200 400 35 + + + + spores 50 + + + − 60 + +− − 65 − − − − 80 − − − − Chaetomium sp. 1.0 × 10⁶ 200 400 35 + + + +50 + + + + 60 + + + + 65 − − − − 80 − − − −

Example 3-1

[0102] (1) Fungi: genera Aspergillus, Penicillium, Byssochamys,Neosartorya and Chatomium.

[0103] (2) Yeasts: genera Saccharomyces and Candida.

[0104] (3) Microorganisms, genus Bacillus, group A: Bacillus subtilisvar. niger and Bacillus subtilis.

[0105] (4) Microorganisms, genus Bacillus, group B: Bacillus cereus andBacillus circulans.

[0106] Each of the microorganisms listed in (1) to (4) (microorganismsreferred to as the group were mixed in equal amounts) was allowed toadhere to the internal surface of a test bottle in an amount of 105 to106 cfu/bottle, and the bottle was fit with a cap. The test bottle was aPET (polyethylene terephthalate) bottle having an internal volume of 500ml, and the test cap was a (polyethylene) cap for an aperture of 28. Theinternal surfaces of the test bottle and cap were each sterilized withhot water in a system selected from those in item 1 below (afterchemical sterilization in the case of 1-3) and then sterilized with achemical in a system selected from those in item 2 below, and theadhering chemical was washed out with aseptic water, and the number ofliving microorganisms on the internal surface of the bottle was measuredto determine the sterilizing effect (challenge test method). The resultsare shown in Table 5.

[0107] 1. Hot-Water Sterilizing Conditions

[0108] 1-1. Hot-Water Spray System

[0109] (1) Sterilization system: a system of spraying a test bottle anda cap with hot water

[0110] (2) Hot-water temperature: 63° C. (on the surfaces of the bottleand cap)

[0111] (3) Flow rate of hot water: 200 ml/sec.

[0112] (4) Sterilization time: 4 seconds with hot water

[0113] (5) Sterilization frequency: twice

[0114] 1-2. Steam Spray System

[0115] (1) Sterilization system: a system of spraying a test bottle anda cap with steam

[0116] (2) Steam temperature: 63° C. (on the surfaces of the bottle andcap)

[0117] (3) Steam pressure: 1.2 kg/cm²

[0118] (4) Sterilization time: 10 seconds

[0119] 1-3. Hot-Pack Charging System

[0120] (1) Sterilization system: a system for charging a test bottlewith a heated content

[0121] (2) Charging temperature: 63° C. (on the surface of the bottle)

[0122] (3) Charging rate: 100 ml/sec.

[0123] (4) Charging time: 5 seconds

[0124] (5) Time after charging: maintained in an inverted state for 30seconds after capping.

[0125] 2. Chemical Sterilization Conditions

[0126] 2-1. Chemical Spray Sterilization System

[0127] (1) Sterilization system: a system of spraying a test bottle anda cap with a chemical

[0128] (2) Preparation of the chemical: Sodium hypochlorite is dilutedwith water and then adjusted to pH 6.3±0.3 with succinic acid as the pHadjusting agent. Polyglycerol fatty ester is used as the surfactant andmixed therewith, and the mixed aqueous solution is regulated at 200 ppmand used as the chemical.

[0129] (3) Effective chlorine concentration: the same as described in2-1.

[0130] (4) Chemical temperature: 50° C.

[0131] (5) Sterilization time: 1 minute

[0132] 2-2. Chemical Charging Sterilization System

[0133] (1) Sterilization system: a system in which the chemical isintroduced into a test bottle and a cap, maintained and discharged.

[0134] (2) Preparation of the chemical: the same as described in 2-1

[0135] (3) Effective chlorine concentration: 400 ppm

[0136] (4) Chemical temperature: 50° C.

[0137] (4) Sterilization time: 1 minute

Comparative Example 1

[0138] Hot-water sterilization only was carried out under the sameconditions as in Example 3-1, and chemical sterilization was notconducted. The sterilizing effect is shown in Table 5.

Comparative Example 2

[0139] Chemical sterilization only was carried out under the sameconditions as in Example 3-1, and hot-water sterilization was notconducted. The sterilizing effect is shown in Table 5.

Comparative Example 3

[0140] Hot-water sterilization only was carried out under the sameconditions as in Example 1 except that the temperature of hot water was40° C. in place of 63° C., and chemical sterilization was not conducted.The sterilizing effect is shown in Table 5.

Comparative Example 4

[0141] Hot-water sterilization and chemical sterilization were carriedout under the same conditions as in Example 3-1 except that thetemperature of hot water used in hot-water sterilization was 40° C. inplace of 63° C. The sterilizing effect is shown in Table 5.

Comparative Example 5

[0142] A test bottle and a cap were sterilized in the same manner as inExample 3-1 except that the sterilization conditions weredescribed-below. The sterilizing effect is shown in Table 5.Sterilization system: A chemical is introduced into the test bottle andcap, maintained and discharged.

[0143] Preparation of the chemical: Oxonia 3% (peracetic acidconcentration 1500 ppm)

[0144] Chemical temperature: 40° C.

[0145] Sterilizing time: 3 minutes

[0146] Comparative Example 6

[0147] A test bottle and a cap were sterilized in the same manner as inExample 3-1 except that the sterilization conditions were describedbelow. The sterilizing effect is shown in Table 5. The chemical used wasa sterilizing having a pH value of 10.

[0148] (1) Sterilization system: A chemical is introduced into the testbottle and cap, maintained and discharged.

[0149] (2) Preparation of the chemical: sodium hypochlorite

[0150] (3) Effective chlorine concentration: 100 ppm

[0151] (4) Chemical temperature: 50° C.

[0152] (5) Sterilizing time: 3 minutes TABLE 5 Example ComparativeComparative Comparative Comparative Comparative Comparative Microbialspecies 3-1 example 1 example 2 example 3 example 4 example 5 example 6Genus Aspergillus ⊚ ◯ ⊚ X ⊚ ⊚ ⊚ Genus Penicillium ⊚ ⊚ ⊚ X ⊚ ⊚ ⊚ GenusByssochamys ⊚ X ⊚ X ⊚ ⊚ ⊚ Genus Neosartorya ⊚ X ⊚ X ⊚ ⊚ ⊚ GenusChaetomium ⊚ ⊚ Δ X Δ ⊚ ⊚ Genus Saccharomyces ⊚ ◯ ⊚ X ⊚ ⊚ ⊚ GenusCandidia ⊚ ◯ ⊚ X ⊚ ⊚ ⊚ Genus Bacillus, ⊚ X ⊚ X ⊚ ⊚ ⊚ group A GenusBacillus, ⊚ X ⊚ X ⊚ X X group B

[0153] In Table 5, ⊚ indicates that no microorganism adhering to thetest bottle was detected, ◯ indicates that 100 to 101 cfu adheringmicroorganisms per test bottle were detected, Δ indicates that 101 to103 cfu adhering microorganisms per test bottle were detected, and Xindicates that 103 to 105 or more cfu adhering microorganisms weredetected.

Example 3-2

[0154] A test bottle and a cap were sterilized in the same manner as inExample 3-1 except that hot-water sterilization was carried out at 80°C. in place of 63° C. The sterilizing effect is shown in Table 6.

Comparative Example 7

[0155] Hot-water sterilization only was carried out under the sameconditions as in Example 3-2, and chemical sterilization was notconducted. The sterilizing effect is shown in Table 6. TABLE 6 ExampleComparative Microbial species 3-2 Example 7 Genus Aspergillus ⊚ ⊚ GenusPenicillium ⊚ ⊚ Genus Byssochamys ⊚ ⊚ Genus Neosartorya ⊚ X GenusChaetomium ⊚ ⊚ Genus Saccharomyces ⊚ ⊚ Genus Candidia ⊚ ⊚ GenusBacillus, ⊚ X group A Genus Bacillus, ⊚ X group B

[0156] In Table 6 similar to Table 5, ⊚ indicates that no microorganismadhering to the test bottle was detected, ◯ indicates that 100 to 101cfu adhering microorganisms per test bottle were detected, Δ indicatesthat 101 to 103 cfu adhering microorganisms per test bottle weredetected, and X indicates that 103 to 105 or more cfu adheringmicroorganisms were detected.

Example 3-3

[0157] A test bottle and a cap were sterilized in the same manner as inExample 3-1 except that hot-water sterilization was carried out at 93°C. in place of 63° C. The sterilizing effect is shown in Table 7.

Comparative Example 8

[0158] Hot-water sterilization only was carried out under the sameconditions as in Example 3-3 except that chemical sterilization was notconducted. The sterilizing effect is shown in Table 7. TABLE 7 ExampleComparative Microbial species 3-3 Example 8 Aspergillus ⊚ ⊚ GenusPenicillium ⊚ ⊚ Genus Byssochamys ⊚ ⊚ Genus Neosartorya ⊚ Δ GenusChaetomium ⊚ ⊚ Genus Saccharomyces ⊚ ⊚ Genus Candidia ⊚ ⊚ GenusBacillus, ⊚ X group A Genus Bacillus, ⊚ X group B

[0159] In Table 7 similar to Table 5, ⊚ indicates that no microorganismadhering to the test bottle was detected, ◯ indicates that 100 to 101cfu adhering microorganisms per test bottle were detected, Δ indicatesthat 101 to 103 cfu adhering microorganisms per test bottle weredetected, and X indicates that 103 to 105 or more cfu adheringmicroorganisms were detected.

Example 3-4 Example 3-1(1)

[0160] A test bottle and a cap were sterilized in the same manner as inExample 3-1. The sterilizing effect is shown in Table 8.

Example 3-1(2)

[0161] A test bottle and a cap were sterilized in the same manner as inExample 3-1 except that the effective chlorine concentration forchemical sterilization was 200 ppm in place of 400 ppm. The sterilizingeffect is shown in Table 4. TABLE 8 Example Example Microbial species3-1{circle over (1)} 3-1{circle over (2)} Aspergillus ⊚ ⊚ GenusPenicillium ⊚ ⊚ Genus Byssochamys ⊚ ⊚ Genus Neosartorya ⊚ ⊚ GenusChaetomium ⊚ ⊚ Genus Saccharomyces ⊚ ⊚ Genus Candidia ⊚ ⊚ GenusBacillus, ⊚ ⊚ group A Genus Bacillus, ⊚ ⊚ group B

[0162] In Table 8 similar to Table 5, ⊚ indicates that no microorganismadhering to the test bottle was detected. TABLE 9 Microbial species pH10pH8 pH6 pH4 pH2 Aspergillus ⊚ ⊚ ⊚ ⊚ ⊚ Genus Penicillium ⊚ ⊚ ⊚ ⊚ ⊚ GenusByssochamys ⊚ ⊚ ⊚ ⊚ ⊚ Genus Neosartorya ⊚ ⊚ ⊚ ⊚ ⊚ Genus Chaetomium ⊚ ⊚ ⊚⊚ ⊚ Genus Saccharomyces ⊚ ⊚ ⊚ ⊚ ⊚ Genus Candidia ⊚ ⊚ ⊚ ⊚ ⊚ GenusBacillus, ⊚ ⊚ ⊚ ⊚ ⊚ group A Genus Bacillus, X ◯ ⊚ ◯ X group B

[0163] The pH value was varied under the same conditions as in Example3-1 (effective chlorine concentration of the chemical: 400 ppm).

[0164] In Table 5, ⊚ indicates that no microorganism adhering to thetest bottle was detected, ◯ indicates that 100 to 101 cfu adheringmicroorganisms per test bottle were detected, Δ indicates that 101 to103 cfu adhering microorganisms per test bottle were detected, and Xindicates that 103 to 105 or more cfu adhering microorganisms weredetected.

[0165] The same test was carried out at an effective chlorineconcentration of 200 ppm, and the same sterilizing effect was confirmed.

1. A method of sterilizing a food packaging container or a food chargingsystem, which comprises a chemical sterilizing treatment which involvescontacting an aqueous sterilizing solution containing a hypochlorousacid-containing, chlorine-based sterilizing agent and a pH adjustingagent with the surface of a food packaging container or the surface of aline pipe, an instrument and a chamber in a food packaging system and aheat sterilizing treatment which involves increasing the temperature ofthe surface to be sterilized, the two sterilizing treatments beingcarried out simultaneously or in separate steps.
 2. The method accordingto claim 1, wherein the aqueous sterilizing solution has a pH value of 4to 8, and is contacted in a heated state at 40° C. to 80° C.
 3. Themethod according to claim 2, wherein the chemical sterilizing treatmentand the heat sterilizing treatment are carried out simultaneously. 4.The method according to claim 1, which comprises a chemical sterilizingtreatment which involves contacting an aqueous sterilizing solutioncontaining a hypochlorous acid-containing, chlorine-based sterilizingagent and a pH adjusting agent combined with a heat sterilizingtreatment which involves increasing the temperature of the surface to besterilized.
 5. The method according to claim 4, wherein the pH of theaqueous sterilizing solution is 4 to 8, and the heat sterilizingtreatment is carried out at a temperature of 63° C. or more.
 6. Themethod according to any one of claims 1 to 5, which further comprisescontacting a surfactant.
 7. The method according to any one claims 1 to6, wherein the hypochlorous acid-containing, chlorine-based sterilizingagent is at least one selected from hypochlorous acid and hypochlorite.8. The method according to any one of claims 1 to 7, wherein theeffective chlorine concentration of the hypochlorous acid-containing,chlorine-based sterilizing agent is 200 to 2000 ppm.
 9. The methodaccording to any one of claims 1 to 8, wherein the pH adjusting agent isat least one member selected from the group consisting of alkali metalhydroxides, alkaline earth metal hydroxides, inorganic acids or saltsthereof and organic acids or salts thereof.
 10. The method according toany one of claims 6 to 9, wherein the surfactant is a surfactant derivedfrom a polyvalent alcohol.
 11. The method according to any one of claims6 to 10, wherein the surfactant is at least one member selected from thegroup consisting of polyglycerol fatty ester, glycerin fatty ester,sucrose fatty ester, sorbitan fatty ester, calcium stearoyllactate,propylene glycol fatty ester, lecithin such as soybean lecithin, yolklecithin and plant lecithin, soybean saponin and beet saponin.
 12. Themethod according to any one of claims 4 to 11, wherein the heatsterilizing step is carried out by using at least one of hot water,steam, hot air and a hot pack.
 13. The method according to claim 12,wherein the heat sterilizing step is carried out as a pre-step of thechemical sterilizing step, and the heat sterilizing step is carried outby using at least one of hot water, steam and hot air.
 14. The methodaccording to claim 12, wherein the heat sterilizing step is carried outas a post-step of the chemical sterilizing step, and the heatsterilizing step is carried out by using a hot pack.
 15. A device forsterilizing a food packaging container or a food charging system,comprising sterilizing agent-contacting means in which an aqueoussterilizing solution containing a hypochlorous acid-containing,chlorine-based sterilizing agent and a pH adjusting agent is contactedin a heated state with the surface of a food packaging container or thesurface of a line pipe, an instrument or a chamber in a food chargingsystem by jetting, dipping or spraying.
 16. The device according toclaim 15, wherein the hypochlorous acid-containing, chlorine-basedsterilizing agent and the pH adjusting agent are contacted in a stateheated at 40° C. to 80° C. with the surface by jetting, dipping orspraying.
 17. The device according to claim 16, wherein the surface iscontacted with the hypochlorous acid-containing, chlorine-basedsterilizing agent, and then the surface contacted with the sterilizingagent is washed with aseptic water by jetting, dipping or spraying. 18.The device according to any one of claims 15 to 17, wherein a surfactantis further contacted.